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Question on 18-wheeler drivetrain

Midlife

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Just curious if anyone knows what a standard 18-wheeler tractor has for the number of gears in the transmission and what a typical rear-end ratio these tractors have.
 
most large trucks these days have 15 gears total. they use a 5 speed transmission, and a 3 speed road ranger gear box in front of that. and yes it does make for some interesting work in the cab in city traffic.
 
When I was driving them 20 years ago, our trucks had 9, 13, 15 or 18 speed transmissions. They were all basically variations of a 5 speed transmission. A 9 speed had a low and high. You would shift 1-5 on the low side, flip a lever to be in high side, skip 1st gear on the high side and use 2-5 again. A 13 speed was the same as a 9 speed with the ability to split each gear on the high side again, so it would go 6low, 6 high, 7lo, 7high, etc. An 18 speed allowed you to split the low side gears, then shift to high side and split those gears again. 15 speeds were a different animal with 5 gears in deep low, 5 gears in low and 5 gears in high (again skipping first on the high side). Deep low was for out in a field loading potatos, Highway driving used low and high. They had a U shaped shift pattern instead of the normal H. 15 speeds were my favorite.

Don't forget that REAL truck drivers only use the clutch to get going from a dead stop. After that all shifting up or down is done by watching the tach and knowing the RPM split between gears!
 
All I know is to do anything possible to avoid lining up behind one on city streets. It's painful to have dozens of cars pass you as you crawl along as the truck tries to get up to speed only to miss EVERY SINGLE light. Block after block. No idea how the drivers have the patience for it.
 
When i was a kid, dad had a B61 Thermodyne Mack Logging truck, that i learnt to drive in.
It had a 4 speed gearbox, 2 speed Joey box & a 2 speed diff. No synchros. I couldnt go for my licence until i could double shuffle all the gears without crunching.
I still remember having my arm hooked through the steering wheel, operating 3 gearsticks together.
When i went for my test, dad put a 24' single axle trailer on the back and i came home with car & heavy combo truck licence. The local copper threw in my bike licence for free!!
 
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